The head of China’s air force has blasted a Japanese Defense Ministry white paper critical of Chinese military drills in and over waters near Japan, saying “the Sea of Japan is not Japan’s sea.”

At a military event Thursday in the city of Changchun, People’s Liberation Army Air Force chief Ma Xiaotian was quoted by state-run media as saying the exercises will continue.

“The Sea of Japan is not Japan’s sea,” the Global Times quoted Ma as saying in response to a question at the event. “We must carry out drills at sea. China’s air force cannot simply stay on guard on land and not venture out.”

A spate of recent Chinese military drills near Japanese territory prompted scrambles by Air Self-Defense Force fighters to hit a new record in fiscal 2016 ended in March this year, the Defense Ministry’s white paper said.

Ma said that while China will continue its military activities, those “in the Sea of Japan are still not that many.”

“What they have said is a bit of an exaggeration,” he added.

Tokyo is concerned that the growing number of Chinese military exercises held in the Sea of Japan and in crucial corridors into the western Pacific could ultimately erode its effective control of the East China Sea.

A dispute over the Senkaku Islands in the East China Sea continues to boil between the two Asian giants. This has prompted concern over prospects of an accidental clash near the tiny islets, which are claimed as Diaoyu in China and Tiaoyutai in Taiwan.

In January, ASDF jets were scrambled after a number of Chinese Air Force bombers and reconnaissance planes were detected flying over the East China Sea and Sea of Japan.

The Chinese planes, including six H-6 bombers, one Y-8 early warning aircraft and one Y-9 surveillance plane, used the Tsushima Strait to fly from the East China Sea to the Sea of Japan and back. They did not enter Japanese airspace.

In July, China’s air force said that its warplanes had conducted long-range drills over the Bashi Channel and the Miyako Strait “several times” during the course of a week. That announcement came after the Chinese Defense Ministry told Japan it should “get used to” the military exercises.

The Miyako Strait lies between the islands of Miyako and Okinawa, while the Bashi Channel separates Taiwan and the Philippines. Both are key entry points into the western Pacific Ocean.

A Chinese defense spokesman said at the time “the parties concerned don’t need to overreact and make a great fuss about it. They will feel better after getting used to such drills.”

Beijing has blasted Tokyo for hyping the exercises, calling them part of “regular” drills, while Japan has said it will keep a vigilant eye on the “expanding and increasing” actions of the Chinese military in the area.

According to data from the Defense Ministry in Tokyo, the ASDF scrambled jets in response to Chinese aircraft a record 1,168 times in fiscal 2016, which ended March 31.